Image decoding device, image decoding method, image coding device, and image coding method

Abstract

The processing amount and coding amount related to decoding/coding of profile information and level information are reduced. The profile/level information decoded by a PTL (profile/level) information decoder (1021) is specified by the semantics of an i-th reference PTL information specifying index at a relative position between i-th profile/level information and referenced profile/level information.

The invention claimed is: 
     
       1. An image decoding device that decodes hierarchically coded data, the device comprising:
 a first decoder configured to decode a profile presence flag indicating whether profile information presents in i-th profile_tier_level (PTL) information; and 
 a second decoder configured to decode the i-th PTL information in a case that the value of the profile presence flag is equal to one, 
 wherein the i-th PTL information is inferred to be equal to (i−1)-th PTL information in a case that the value of the profile presence flag is equal to zero. 
 
     
     
       2. The image decoding device according to  claim 1 ,
 wherein the i-th PTL information includes at least a profile space, a tier flag, a profile identifier, and a profile compatibility flag. 
 
     
     
       3. An image decoding method for decoding hierarchically coded data, the method comprising:
 decoding a profile presence flag indicating whether profile information presents in i-th profile_tier_level (PTL) information; and 
 decoding the i-th PTL information in a case that the value of the profile presence flag is equal to one, 
 wherein the i-th PTL information is inferred to be equal to (i-1)-th PTL information in a case that the value of the profile presence flag is equal to zero. 
 
     
     
       4. An image coding device that hierarchically codes image data, the device comprising:
 a first coder configured to code a profile presence flag indicating whether profile information presents in i-th profile_tier_level (PTL) information; and 
 a second coder configured to code the i-th PTL information in a case that the value of the profile presence flag is equal to one, 
 wherein the i-th PTL information is inferred to be equal to (i−1)-th PTL information in a case that the value of the profile presence flag is equal to zero. 
 
     
     
       5. The image decoding device according to  claim 1 , wherein in a case that the value of the profile presence flag is equal to zero, a value of a sub-layer profile present flag is equal to zero, and the sub-layer profile present flag indicates whether the profile information presents in the i-th PTL information for a sub-layer.